Learn

What are peptides?

Short chains of amino acids that act as the body's signalling molecules. How they work, how they're given, and the families you'll actually hear about.

A simple definition

A peptide is a short chain of amino acids. Amino acids are the building blocks of protein — so a peptide is basically a very small piece of protein. Usually 2 to 50 of them linked in a row. Longer chains are called proteins.

• Your body already makes thousands of them. They’re messengers: they carry instructions between cells.
• Each one fits a specific receptor — a docking point on a cell — like a key fits one lock. That’s why tiny doses can do one specific job.
• None of this is new. Insulin was the first peptide medicine, back in 1922. Semaglutide works the same way, a century later.

How they work in the body

Nearly all of them work the same basic way: they copy a signal your body already sends, or make it louder. (The technical word is agonist — something that switches a receptor on.) Four of these cover almost everything here:

• Appetite hormones copied (semaglutide, tirzepatide, retatrutide) — they copy gut hormones that tell your brain you’re full, and slow how fast your stomach empties. This is the weight-loss group.
• Growth-hormone releasers (sermorelin, CJC-1295, ipamorelin, tesamorelin) — instead of injecting growth hormone, these tell the gland in your brain that makes it to release more of your own.
• Repair peptides (BPC-157, TB-500) — these act on how your body grows new blood vessels and moves repair cells into damaged tissue. That’s why they’re used for injuries.
• Melanocortin peptides (PT-141, melanotan) — these work on brain pathways for sexual desire, and on the cells that make skin pigment.

Why they're injected

• Peptides are fragile. Swallow one and your stomach breaks it apart before it can do anything.
• So nearly all are injected just under the skin, into the fat layer. That’s what “subcutaneous” means.
• A few are exceptions — some nasal sprays, and MK-677, which is a tablet because it isn’t technically a peptide.
• That same fragility is why storage and preparation matter so much.

The main families

Learn

Uses & the honest evidence

Class by class: what it's used for, and how strong the human evidence really is.

Side effects by class

Learn

Research & clinical case studies

Landmark trials in plain English — who was studied, what happened, how strong it is. The gap between what's claimed and what's been proven in humans is the whole story of this space.

References

• Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med 2021. doi:10.1056/NEJMoa2032183
• Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med 2022. doi:10.1056/NEJMoa2206038
• Tesamorelin in people with HIV on integrase inhibitors. AIDS 2024. PMC11365754
• Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity (Phase 2). N Engl J Med 2023. doi:10.1056/NEJMoa2301972
• Eli Lilly. Retatrutide TRIUMPH Phase 3 topline results, Dec 2025 (investor release)
• Pickart L, Margolina A. Skin Regenerative and Anti-Cancer Actions of Copper Peptides. Cosmetics 2018 (MDPI)
• BPC-157 human trials — systematic review summary, 2025 (peptide-db)
• Nass R et al. Ghrelin mimetic MK-677 in healthy older adults. Ann Intern Med 2008

Where a journal link is paywalled, the DOI locates the paper. Secondary sources only summarise underlying trials.

Learn

Fifteen facts worth knowing

The science, the market and the safety realities — fast orientation, sourced. Split by theme.

The science

Medicine & the market

Safety & the grey market

Expanded with citations across the handbook: Research for the evidence · Statistics for the numbers · Dosing for the units · Check a COA for the safety points.

Learn

The boom, in numbers

Market size, GLP-1 sales, how common use has become, and the state of the evidence. Every figure sourced; the audited sales are the hard numbers, projections are direction only.

GLP-1 drug sales, full-year 2024

The market, and its uncertainty

Peptide-therapeutics market projections vary wildly — roughly $87bn to $295bn by the early-to-mid 2030s depending on definition. Treat as direction, not precision. What's not in doubt: North America held ~60% of the market in 2024, and peptide contract manufacturing is forecast to hit ~$5.7bn by 2030 (~12.5%/yr), driven overwhelmingly by GLP-1 demand.

Directory

67 peptides, rated honestly

Every compound you're likely to hear about — profile, evidence badge, commonly-reported dosing where one circulates, and one safety note. Inclusion is never a recommendation.

Profiles compiled from regulator announcements (MHRA, FDA, EMA), peer-reviewed trials and company releases, current to mid-2026. Fast-moving field — verify anything important against primary sources.

Directory

Compare any two

Category, mechanism, evidence, reported dosing and safety, side by side. Popular pairs get full write-ups on Head-to-heads.

Dosing

Dosing, injecting & cycling

Units, kit, routes, sites, technique, timing, stacking and cycling — the complete practical picture.

Units: the 1,000× trap

1 milligram (mg) = 1,000 micrograms (mcg). GLP-1 medicines are dosed in milligrams weekly; many GH and research peptides are quoted in micrograms. Mixing the units is a thousand-fold error — the entire distance between a normal amount and a dangerous overdose lives in one letter. Check the unit before anything else, every time.

Storing peptides

Needles & kit

Two jobs, two needles: moving liquid (thicker, faster) and injecting (as fine as possible). Gauge = thickness; higher number = thinner.

Plus alcohol swabs, bacteriostatic water, clean hands, and a sharps bin. Needles are single-use — reuse blunts them, sharing risks bloodborne infection, neither is negotiable.

Subcutaneous vs intramuscular

Subcutaneous (subQ) = into the fat under the skin with a short fine needle — the route for GLP-1 medicines, tesamorelin, and nearly everything else here. Intramuscular goes deeper, absorbs differently, and is uncommon for these compounds. Everything below is the subQ route.

Injection sites & rotation

Safe technique, step by step

Standard subcutaneous technique — same method as insulin. First-timers should have a nurse or pharmacist demonstrate. That's the best move, not a disclaimer.

1. Wash hands properly — soap, water, no shortcuts.
2. Check the solution: clear, particle-free, in date. Confirm the amount and the unit.
3. Swab the vial stopper and the skin; let both air-dry.
4. Draw the dose, flick out air bubbles, expel the air.
5. Pinch a fold of skin to lift fat away from muscle.
6. Insert in one smooth motion — 90° for short insulin needles, 45° if very lean.
7. Inject slowly and steadily; release the pinch.
8. Withdraw at the same angle; light pressure with clean gauze — don't rub.
9. Needle straight into the sharps bin. Never household waste, never recapped.
10. Log it: site, amount, batch number, time.

Timing, by class

• GH secretagogues (ipamorelin, CJC-1295, sermorelin) — bedtime, empty stomach, 1–2h after food. Rides the natural night-time GH pulse; food blunts it.
• MK-677 (oral) — same time daily, often evening. Long half-life; affects sleep and appetite.
• GLP-1 medicines — same day each week, any hour, fed or fasted. Consistency beats clock-watching.
• Healing peptides (BPC-157) — often split morning/evening. Community habit; no established human schedule exists.

Stacking — the honest picture

"Stacking" = running multiple compounds at once — the classic CJC-1295 + ipamorelin pairing, or BPC-157 + TB-500. People stack for theoretical synergy; what it actually multiplies is unknowns: more side-effect sources, more interactions, more contamination exposure, and no way to attribute anything.

• One at a time. Run a single compound 1–2 weeks before adding anything, so reactions can be traced.
• Don't mix unknowns in one syringe unless compatibility is actually established.
• Mind total load — more compounds = more injections = more sterility risk.
• Short and simple beats long and experimental — and a clinician should steer any combination.

Cycling & receptor tolerance

A period on, a period off. Rationale: receptor desensitisation — hammer a receptor continuously and it responds less, so a break is thought to reset it. Sound pharmacology; but the specific schedules quoted online (the classic "12 on, 4 off" for GH secretagogues) are community conventions. Nobody has trialled them.

Licensed schedules (reference)

Dosing

Reconstitution & dose reference chart

The commonly reported figures for 25+ compounds in one place — a typical vial, the water people add, the concentration that results, the syringe units that equals, and the dose/frequency/cycle patterns you'll see quoted.

* Units on a U-100 insulin syringe (100 u = 1 mL), valid only for the example mix in the same row. † A 200–600 mg glutathione amount exceeds one insulin syringe at this concentration — exactly what the calculator exists to catch. "Of each" in blends = one injection delivers that amount of every component simultaneously. Compiled from vendor sheets and community sources, cross-checked against licensed product information where one exists; for unlicensed compounds these are not clinically validated.

Dosing

How to reconstitute a peptide

Peptides arrive as freeze-dried powder that has to be dissolved before it can be measured. The standard method, the five moves, and the maths.

What reconstitution is

Peptides ship lyophilised — freeze-dried into a white pellet, stable while dry. Reconstitution just means adding a sterile liquid so it becomes measurable.

• Bacteriostatic water is the standard diluent — its preservative keeps a mixed vial usable ~4 weeks in the fridge.
• Plain sterile water has no preservative — a vial mixed with it is vulnerable within hours.
• The end product is injected, so sterility is the whole game — contamination means infection or worse.
• Bacterial endotoxin survives sterilisation and never shows on the HPLC purity tests vendors publish.

The kit

• Vial of lyophilised peptide
• Bacteriostatic water
• Alcohol swabs — for both rubber stoppers
• Sterile single-use syringe to move the water
• Clean, flat surface

The five moves

1. Swab both stoppers. Fresh alcohol wipe on both vials' rubber tops; air-dry. The most commonly cut corner and the likeliest contamination point.
2. Draw the bacteriostatic water. The amount is a concentration choice, not a fixed rule — more water = weaker, easier-to-measure solution. Calculator below.
3. Run it down the glass, slowly. Tilt the peptide vial, let water slide down the inside wall. Never jet it onto the powder — shear force can damage the peptide. The step that matters most.
4. Swirl, never shake. Most peptides dissolve in a minute or two; roll gently if needed. Shaking foams and can denature. Result should be completely clear.
5. Refrigerate, labelled with the date. 2–8°C, out of light, ~4 weeks with bacteriostatic water. Never freeze a mixed vial.

The calculator

U-100 insulin syringe: 100 units = 1 mL. Concentration = peptide ÷ water. Worked arithmetic — never carry a unit figure from any chart to a different vial.

Storage & when to discard

Mixed vials: refrigerated, dark, dated. Discard if cloudy, particulate, past the preservative window, or stored warm. When in doubt, throw it out.

Dosing

Microdosing vs one larger dose

The buzziest dosing idea going. The theory is real pharmacology; the evidence it delivers better outcomes is thin to absent.

Two meanings circulate: splitting the same total into frequent small injections, or deliberately running below standard doses (common with GLP-1s to save money or dodge nausea). This page compares frequent-small vs one-larger.

Where the theory holds

• Split the same total into smaller doses → flatter blood levels, no peak-and-crash.
• GH releases in pulses anyway — frequent small doses arguably mimic the rhythm.
• Many side effects track the peak → lower peak could mean a smoother ride.

Where it runs into reality

• Side effects can just return more often. Smaller doses clear faster — re-dose and the same effect can come straight back rather than being avoided.
• More injections = more risk events. Every extra jab is another site reaction, infection or technique-slip opportunity, and tiny part-draws are imprecise plus another contamination chance each time.
• For licensed GLP-1s the studied schedule is standard titration under a prescriber. No clinical body endorses DIY microdosing, and no evidence shows it matches the trial results.
• It does nothing about the vial. Microdosing an unlicensed peptide makes it no purer and no better labelled. Sourcing risk identical at any injection frequency.

Bottom line: pharmacokinetic theory, cost and anecdote drive this choice — not outcome data. Pair with the chart, Check a COA and Responsible use.

Dosing

Common peptide stacks

The combinations that actually circulate, grouped by goal — what each stack is, what's in it, how each part is dosed, and the cycle. Reported figures, not protocols.

Fat loss & recomp

Muscle, size & sleep

Recovery & repair

Energy & longevity

Stay safe

Take this to your GP

This handbook says "talk to a clinician" on nearly every page. Here is how to actually have that conversation — what to say, what to ask, what to bring. Print it or screenshot it.

Say it plainly

That sentence does three things: it's honest, it removes the pressure to prescribe, and it asks for something they can actually give you.

Six questions worth asking

1. Given my history, is there any reason this would be riskier for me than for most people?
2. Can we do baseline bloods — full blood count, HbA1c and fasting glucose, liver, kidney, lipids, and IGF-1 if it's a growth-hormone compound?
3. Does it interact with anything I'm already on, including the contraceptive pill?
4. What symptoms should make me stop immediately and contact someone?
5. If I'm after weight loss — am I eligible for a licensed medication on prescription or through an NHS service?
6. Can we recheck bloods in 8–12 weeks so we're comparing against my own baseline?

Bring this with you

• The exact compound name and, if you have it, the batch number and the COA.
• Dose, frequency, and how long you've been taking it or intend to.
• Everything else — prescriptions, supplements, TRT, alcohol intake, recreational anything.
• Your goal, honestly. "Lose four stone" gets different advice from "get my arm right for rugby".

Kondition

Where coaching fits

This handbook doesn't sell compounds and never will. But it's published by a coaching business, and it's fair to be direct about what we actually think works.

The honest position

If you read this whole site, one pattern shows up on nearly every page: the licensed medicines do something real, most of the grey-market compounds don't have the evidence people think, and none of them do the work.

A GLP-1 removes the appetite problem. It doesn't build a body, teach you to eat, or make you strong. Left alone it takes muscle out with the fat, and the weight tends to find its way back when it stops. That isn't an argument against the drug — it's an argument for having the rest of it handled.

What we actually do

If you want the work done properly

Have a look at what it’s produced for other people, watch how the coaching actually works, or just drop me a message and I’ll tell you honestly whether we can help.

See client results →  ·  Instagram →  ·  konditioncoaching.co.uk →

Kondition

How this was built

Who wrote this, where the information comes from, how the ratings are decided, and how to tell us we've got something wrong.

Who publishes it

Kondition Coaching — a UK online coaching business. This started as an internal reference so our coaches could answer client questions about peptides accurately instead of guessing, and grew into something worth making public.

We are coaches, not clinicians. We can read and summarise evidence. We cannot examine you, run your bloods, or tell you what's safe for your body — and we won't pretend otherwise.

Where the information comes from

1. Regulators first — MHRA, FDA and EMA announcements, approvals, warnings and safety communications.
2. Then peer-reviewed human trials — preferring randomised controlled trials and systematic reviews. Where a landmark trial exists, we link it directly.
3. Then primary reporting — company trial results and investor releases, clearly labelled as such.
4. Community and vendor sources are used only to describe what circulates (reported doses, common stacks) — never as evidence that something works, and always labelled.

How the ratings are decided

These are editorial judgements, not a validated scoring system. They're shown so you can see our reasoning and disagree with it.

Independence

• No vendor sponsorship. Nobody pays to appear here or to be rated a certain way.
• No affiliate links, anywhere on this site. We don't earn a penny if you buy anything.
• No products sold. Kondition sells coaching. That's the entire business model behind this page.
• Inclusion is not endorsement. Several compounds here exist in the directory specifically so we can tell you to avoid them.

Currency & corrections

Last reviewed: 20 August 2026. Content is current to mid-2026. This field moves fast — approvals, trial results and regulator positions change, so verify anything important against the primary source before relying on it.

If something here is wrong, out of date, or misleading, tell us and we'll fix it and note the change. Corrections from clinicians and researchers are especially welcome. Reach us via konditioncoaching.co.uk/contact.

Dosing

Stopping & keeping it off

The question almost nobody asks until it's late: what happens when you stop? This is the honest answer, with the trial data — and what actually decides whether the weight stays off.

What the trials actually found

Why it happens

• Appetite rebounds. The signalling that suppressed hunger stops. Food noise returns — often sharply, and often within a fortnight.
• You need fewer calories than before. A smaller body burns less, so the intake that held your new weight is lower than the intake that held your old one.
• If you lost muscle, that gap is worse. Lean tissue is metabolically active. Losing it lowers the ceiling further — see keeping muscle while you lose fat.
• The habits were never tested. If the drug did all the restraint for a year, nothing was learned that survives without it.

What people do instead of stopping dead

These are approaches discussed in clinical practice — the specifics are a prescriber's call, not ours.

What actually holds the result

Sources: STEP 1 trial extension (Diabetes Obes Metab 2022) · SURMOUNT-4 (JAMA 2024). Figures are trial averages; individual outcomes vary widely.

Dosing

Keeping muscle while you lose fat

Every big calorie deficit costs some lean tissue — GLP-1s included. Here's what the body-composition data shows, and what actually protects it.

What the data says

• In trial body-composition substudies, about 25–33% of total weight lost was lean mass — the SURMOUNT-1 substudy put tirzepatide at roughly 75% fat / 25% lean.
• Real-world cohorts where people trained and ate enough protein look considerably better, with the large majority of loss coming from fat.
• Studies pairing a GLP-1 with structured resistance training and adequate protein consistently report better lean-mass retention than the drug alone.
• Some lean loss is normal and expected — a smaller body carries less supporting tissue. The goal is limiting it, not eliminating it.

What protects it

Sources: SURMOUNT-1 body-composition substudy · GLP-1 body-composition meta-analyses (2026) · protein and resistance-training literature in energy deficit. Figures are averages across trials.

Stay safe

Responsible use, bloodwork & health checks

What careful, medically supervised use looks like — the checks, the monitoring rhythm, the stop-signs. Read this page before acting on anything else in the handbook.

The golden rules

1. Clinician first — ideally one who knows the specific compound; full honesty about everything being taken.
2. Baseline bloods before anything — so change is measured against the person's own normal, not a guess.
3. One change at a time — three compounds at once means never knowing which helped or hurt.
4. Lowest effective amount — most side effects scale with dose; more is not better.
5. Verify the product — independent COA, ideally own-sample testing. See Check a COA.
6. Sterile technique, every time — see Reconstitution.
7. Track everything — amounts, timing, batch numbers, symptoms, blood trends.
8. Know when to stop — have the red-flag list before it's needed.

Baseline bloodwork

A sensible baseline catches problems that make peptides a bad idea in the first place — undiagnosed diabetes, kidney or liver issues, cardiac risk. Compound- and person-dependent; a broad panel commonly includes:

Ongoing monitoring

Not one-and-done. Sensible rhythm: baseline → re-test 6–8 weeks → every ~3 months while continuing, plus whenever dose changes or something feels off. Bring the clinician the trend, not one number.

Red flags — stop and seek care

• Severe allergic reaction — face/throat swelling, breathing difficulty, widespread rash: emergency, 999.
• Injection-site infection — spreading redness, heat, swelling, pus, fever.
• Severe or persistent abdominal pain (possible pancreatitis, especially on GLP-1s), or pain boring to the back.
• Chest pain, palpitations, fainting, persistently racing heart.
• Sudden vision changes, severe headache, new neurological symptoms.
• Low blood sugar signs — shaking, sweating, confusion; higher risk alongside insulin or sulfonylureas.
• Any new or changing mole or lesion — especially around melanotan-type products.
• Persistent vomiting, jaundice, dark urine.

Who shouldn't go near this

• Pregnant, trying to conceive, or breastfeeding.
• Current or past cancer — growth-promoting compounds especially.
• Uncontrolled diabetes, heart, liver or kidney disease.
• Personal or family medullary thyroid cancer / MEN2 — hard contraindication for GLP-1s.
• Competing in tested sport.
• On insulin or sulfonylureas (hypoglycaemia risk with GLP-1s) or anticoagulants (bleeding considerations with any injectable).

What else you're taking

Most peptide harm in the real world comes from a combination, not a single compound. These are the interactions worth raising with a clinician before anything else.

Women: what's different

The shape of a supervised first 12 weeks

What a properly monitored start actually looks like — descriptive, so you can tell whether the care you're getting is thorough or careless.

1. Before day 1 — history, contraindications checked, baseline bloods drawn, a clear list of what should make you stop.
2. Weeks 1–2 — lowest dose. Side effects typically appear here and often settle. Appetite drops noticeably on the incretins.
3. Weeks 2–4 — first step up if tolerated. Nausea usually tracks the increases, not the drug in general.
4. Weeks 6–8 — repeat bloods and compare against your own baseline, not a reference range. Dose reviewed against response.
5. Weeks 8–12 — the honest review: is this doing what it was meant to, at what cost, and what's the plan for coming off? Rate of loss checked against whether strength is holding.

Getting checks in the UK

GP first if there are symptoms or underlying conditions. Regulated private blood-testing services cover baseline and hormone panels without referral. Either way: whoever interprets the results needs the full picture of what's actually being taken.

Stay safe

The grey market & bogus sellers

Why an unregulated "research chemical" market exists, what's actually been found in vials, and how to tell merely-risky from outright scam.

• Unapproved peptides can't legally be sold for human use in the UK or US — so they're sold anyway, labelled "for research use only".
• Regulators call that label a legal fiction; the marketing winks at exactly the opposite.
• Enforcement is climbing — the FDA fired off 50+ warning letters to peptide sellers in September 2025 alone.
• Social-media demand + cheap overseas manufacturing + a regulatory gap = a fast market with no built-in quality guarantee.

What's actually been found in vials

Lessons from community scam-tracking

• Contaminants purity tests never look for. Community screening has returned preliminary positives for dangerous adulterants — including fentanyl — in grey-market vials. "99% pure" by HPLC was never designed to catch that.
• Labs only test what's paid for. No contaminant line on a COA ≠ passed — usually means nobody checked. Screening often happens only after a scare.
• Same powder, many brands. Much grey stock is hand-relabelled from a few source manufacturers — a "trusted brand" may be the same batch in new packaging.
• Sellers vanish and rebrand. Unanswered messages, deleted groups, surprise substitute vials, sudden price hikes — the standard exit before a rebrand.

Field reporting distilled from community scam-tracking (K-Hole / @Krysia830073) plus FDA warning letters, TGA and Health Canada notices, and community lab investigations. Treat preliminary community findings as reason for caution pending confirmation — but don't dismiss credible safety warnings while waiting.

Stay safe

How to check a COA is real

A Certificate of Analysis is only as good as its source. What one should contain, how fakes give themselves away, and how to test a product independently.

What a COA should contain

Supplier, the independent testing lab, product and batch/lot number, results, and a date. The tests to expect:

Spotting a fake

• Verify on the lab's own portal. Reputable labs give each report a unique key or QR checked on their site. A forger can fake a PDF, not a record in the lab's database.
• A named, independent lab. A certificate wearing only the seller's branding is self-made and worthless.
• Check the client field. Different company named? Borrowed COA describing someone else's product.
• Match batch number and date on the physical vial to the certificate. A COA validates one batch, ever.
• Fabrication tells: "100.00%" purity, perfectly symmetrical peaks with no baseline noise, identical COAs across products, dead verification links, mismatched dates.

Labs the community actually uses

Aggregators (Finnrick, VialAudit, PeptideBenchmark) collate results but run no assays — context, not proof. Posting a sample for HPLC + identity (+ endotoxin at fuller labs) sidesteps vendor cherry-picking; typical turnaround 1–2 weeks; contact the lab first for sample size and submission steps.

Stay safe

Who actually makes peptides

From the pharma giants behind the GLP-1s to contract manufacturers, compounding pharmacies, and the independent labs vetting the grey market.

The pharmaceutical originators

• Novo Nordisk — semaglutide (Ozempic, Wegovy, Rybelsus): a ~$31bn franchise in 2024.
• Eli Lilly — tirzepatide (Mounjaro, Zepbound): ~$45bn total 2024 revenue, driven by it.
• Full GMP manufacturing and regulatory oversight — the standard the grey market cosplays.

Contract manufacturers (CDMOs)

Most peptide active ingredient is actually made by specialist contract manufacturers, and GLP-1 demand triggered a historic capacity build-out:

• Bachem (Switzerland) — leading pure-play peptide CDMO, expanding Swiss + California sites.
• PolyPeptide Group (Switzerland) — six GMP sites since 1952; agreed a ~$1.8bn acquisition by Samsung Biologics in July 2026, the largest Korean biopharma deal to date.
• CordenPharma — investing €1bn+ into peptide capacity.
• Plus SK Pharmteco, Almac, Axplora, Neuland Laboratories.

Compounding pharmacies (503A vs 503B)

• 503A = patient-specific compounding; 503B = larger scale under stricter FDA oversight.
• During the 2022–25 GLP-1 shortages, compounded semaglutide/tirzepatide were widely and legally available.
• Shortages declared over (Dec 2024 / Feb 2025) — the FDA has moved to shut the compounding route.

Independent testing labs

The community's quality backstop — Janoshik Analytical (Prague) is most used: HPLC purity, mass-spec identity, endotoxin, metals and sterility with QR-verifiable certificates. Key caveat: not ISO 17025 accredited, results unsuitable for regulatory submission — a community vetting tool. Accredited alternatives: Vanguard Laboratory, MZ Biolabs. Full table on Check a COA.

Stay safe

Peptides & UK law

How peptides are regulated in the UK — licensed medicines, the "research use only" zone, selling and importing, and anti-doping. General information current to mid-2026, not legal advice.

The short version: medicines are regulated by the MHRA under the Human Medicines Regulations 2012. A peptide's legal position depends on what it is and how it's supplied: a few are licensed medicines, most are sold as "research chemicals", and selling any of them for human use without a licence is unlawful.

The clear-cut example: melanotan

The MHRA has repeatedly warned that Melanotan I and II tanning injections and nasal sprays are unlicensed medicines, illegal to sell in the UK, and unsafe. The general rule in one product: no licence + sold for human use = unlawful, however it's marketed.

Anti-doping

Separately from criminal law: GH secretagogues, IGF-1, TB-500 and similar are explicitly on the WADA Prohibited List, and unapproved compounds like BPC-157 are caught by the non-approved-substances rule. Anyone in tested sport treats every peptide in this handbook as bannable.

Sources: Human Medicines Regulations 2012 (legislation.gov.uk) · MHRA warnings on melanotan/unlicensed injectables (gov.uk) · UK Anti-Doping prohibited list (ukad.org.uk).

Start here

What’s your goal?

Pick what you’re actually trying to achieve. You’ll get the honest verdict, what the evidence says works, and every compound people use for it — rated.

Reference

The big head-to-heads

Seven comparisons that come up constantly — table first, verdict after. Build your own on Compare.

Reference

Glossary

Plain-English definitions for the terms that come up most in this handbook. Type to filter.

Reference

Straight answers

The questions people actually ask, answered without hedging. Education, not medical or legal advice.